The present invention relates to a pressure sensor.
More particularly the present invention relates to a pressure sensor which has a housing and a sensor element composed of a piezoresistive material and arranged in the housing. In the case of such a pressure sensor, known from German Offenlegungsschrift 31 25 640.6, the piezoresistive measuring elements, such as for example thick-film resistors of cermet, contactive plastic or metal, are printed on a base. The resistor element and the base are arranged as close as possible to the pressure chamber in order to be able to determine the prevailing pressure. Furthermore, the measuring signal is passed with the aid of electric leads to an electronic evaluation circuit arranged outside the housing of the pressure sensor. As a result, the piezoresistive elements and the electronic components have to be elaborately connected to one another with the aid of sheathed leads. Since the piezoresistive measuring element is exposed directly to the pressure, it is also exposed to the high temperatures prevailing in the combustion chamber. The flames spread there at a temperature of about 2000.degree. C., whereby stresses can occur in the housing. As a result, the pressure signal is falsified by the high temperatures.
Furthermore, European Preliminary Published Specification 85 111 895.0 discloses a pressure sensor in which the thick-film resistor is arranged on the bottom of a base. However, this pressure sensor is intended only for determining the pressure in distributor pumps. The high temperatures prevailing in the combustion chamber would falsify the measuring signal in the case of this design as well.